Magnetic separator



June 13, 1950 R. H. STEARNS 2,511,484

MAGNETIC SEPARATOR Filed April 26, 1945 2 Sheets-Sheet 1 *3 IN VEN TOR. )POSWZZZ l7. 3764/9/15 June 13, 1950 R. H. STEARNS MAGNETIC SEPARATOR 2 Sheets-Sheet 2 Filed April 26, 1945 IN V EN TOR 'AUJ'h/fll fl. 57/54/6145 ATTOIP/Vf Y Patented June 13, 1950 UNITED: STATES OFFICE;

MAGNETIC SEPQXRATOR:

Roswell H. Stcarns; Wauwat saiW ss 'snor to StearnsMa netic Mf o-M waukee. W s, corpor ion oiwisc n Application-April: 26, 1945;, Serial No;..5,9,0;3,68a

7; Claims," (Cl.,2D&1--2,23")

This; invention relates; to; magnetic; separators designed .for; concentratio of ores and: minerals by: the lift method; a e p cially; directedto a magnetic-s parates f r; epar ing: highly: complex mixtures of materials; varying in magnetic permeability t'os a; grgeater on lesser degreeor being of. substantiallyequalipermeability but varying specific; gravity: v

Objects; of; this invention: areto=provide.- aema'g netic; separa r: which has; on r --.mag,netic assembliesyeach. providing a pair of air; gaps through which the material;pas s es, which isso arranged,v that; a; plurality: oi graded, separations are: obtained. at each" airap and w h a in l passagerof 'theymaterial therethrough, so that-the separator; provides 1 not only a pl r y i difiert s parated products. f r ch ma n t assembly but also provides aplurality of difie 'entseparated products for eachmainmagnetic field ateach air ap Furtherobjects are teprovidela, magnetic separator'in' which a: plurality. of zones-of separation are provided at each, ai-rgap, in which theitotal intensity for all of the zonesat any aingapmay be simultaneously adjusted and in. which the relative intensity between successive: zon s; at each air gapmay be adjusted to thereby, provide an-y'degree of differential separationdesiredv for each air gap, and also tov control; the total. in tensityat the'air gap for alliof-l the-zones,

Furtherobjectsare to provideamagnetic sop.- arator in which a plurality of different zones are pnovided at each, air gapv and; are arranged in increasing intensity so that as the material, is passed through an air gap the magnetie-material is premagnetized, as it passes from zone to: zone and acertaininterval of time is, allowed or, the travel of the: material through one zone: to thus allow time'for premagnetizationof the magnetic material before it passesinto the next adjacent more intense. zone.

Further objects are to provide a magnetic separator which will provide a. greater range of separation of the-materialsfor a. given number of magnetic assemblies than has. heretofore; been possible, and inv which each: magnet. assembly functions as a pluralityof individual separators for securing; a largernumber of. graded, separated products from a. single passage through the machine, the: invention lending itself to greater flexibility so that 01191,,tXVO or any number of 2 a idewhicheis,thoro l hlx reliablein its operation.

Embodiments otthe-inventionare shown in the accompanying; drawings, inwhich:

Figure; 1- s d lcva l c iiv par ly ken awai with pa ns ct o sh n ne:v i rmof the invention.

Eigure; 21-. a,- plan view, of the structure. shown n F eu -e 11 Figure 3 is -.-a sectional view on theline, 3,3,of Bignrerm Eigure, 4 1s. ascetionalview on .theline 4-,.-Jli of Eia r e ie Eigure; 5 is,v as sectional view, on, the line 5x5, of 'Eigur e li'.

Eigur ,6" is-adetailed-viewpartly broken away an nar tly n-sect i n frcm he side opposite hat-s own in: F gure Eig -ure '7 is: a sectional view on theline 11-1 of F -igureyti:

l ig urev 8;- is a fragmentary longitudinal elevational-yviewlpartly; in section, of a modified, form of, the invention.

The m net pa a r a ompr se: a-sinsle rgaplnralityof magnetassemblies. In the for-m ohos'en for illustration in Figures 1, 2, and 3, two maghetiassemblies. have been illustrated andale indicated by; thesreference characters Aland, B. The masne ras embly A is provided w th apai of energizing windings I and; 2- wound about yoke-e on core; portions 3 and 4 respectively. The core: lisiprovidc'd. w th p e p ece nd; i and the: a e: 4-: sim ar y ro ed w h pol p ece and i3.

sim larly the-magnet assembly; B, is provided with energizing windings 9v and It: Wound about mkeor cote pertions I1 and It, The core H is provided. with; pole pieces iii-and; M and the core [2; isprovided: with, pole pieces [5 and It.

It isiprefeizableto provide :the usualrneanssuch as; a rheostat, not howmior adjusting the value 0; the: current, passing through the energizing windings; of the, magnet assembly. Also it is prefeliabletdhaveamore powerful magnetic field fonthe mag-net assembly 13. tha for theima -net assembly A3,

'l he polepieces at. each end of each magnet assembly. are.- spacedapart, to, provide. air gaps through; which a; continuous feed belt indicated by the reference, character ll, passes. This feed belt/.is-suppliedwith material to be separated by any suitable supply means such, for instance, as thechute= [8,, Any suitable means are provided for insuring a-uniform even spreading of the material, uponthe, feed, belt. The, feed belt is driven from "theleft-hand end ofthe machine as viewed in Figures 1, 2, and 3 adjacent the feeding means or chute 16. For instance, the driving pulley I9 is driven from a variable speed reduction gear motor indicated by the reference character 20. The othe end of the feed belt is supported by the idler pulley 2| and a spacing pulley 22 is provided to hold the belt spaced sufficiently downwardly to provide adequate clearance between the lower stretch of the belt I1 and the overhanging portions of the machine. Attention is particularly directed to Figure 3 and it will be noted that the manner of driving the belt is contrary to the usual practice. Ordinarily the pulley 2| would be the driving pulley and would pull the belt through the machine causing the upper stretch to be tight. Instead the driving pulley is the pulley IS. The reason for this is that the lower stretch of the belt is held taut whereas the upper stretch of the belt is allowed to sag slightly for a purpose hereinafter to appear. In order to increase this effect a brake 2| may be provided to produce a slight braking action for the pulley 21. The lower magnet structure of each unit is carried by transverse channels or box-like structural steel members 23 which are supported by side frames 24, see Figures 3 and 4. The upper magnet structure of each magnet assembly is similarly supported by transverse channels or box-like structural steel members 24. Each magnet structure is preferably secured in any suitable manner, not shown, to the corresponding transverse supporting members 23 or 24. The upper members 24 are supported from the lowe members 23 by means of bolts 25. These bolts are of nonmagnetic material such, for example, as stainless steel and are threaded for a considerable distance at each end. Nuts 26 are screwed on the bolts and engage opposite sides of the members 23 and 24. By this means either or both ends of the magnet structure may be adjusted to any degree desired, either the same amount at both ends or different amounts at opposite ends as sufficient clearance is provided for the bolts 25. Obviously if desired, the faces of the nuts 26 adjacent the members 23 and 24 may be rounded and the members 23 and 24 may be slightly socketed. This construction, however, has not been illustrated as it is believed to be a well known mechanical construction.

The upper pole 5 of the magnet assembly A is provided with a plurality of V-shaped projections or sub-poles 21 and the pole 6 is similarly provided with a plurality of V-shaped projections or sub-poles 28. These sub-poles 21 and 23 produce separating zones as will appear as the description proceeds. Take-off belts 39 and 3| are provided for the sub-poles 21 and 28.

The magnet assembly B is similarly provided with take-off belts 32 and 33. The pole 13 of the magnet assembly B may be provided with a plurality of V-shaped sub-poles 34 and if desired the pole piece i l of the magnet assembly B may be provided with a single V-shaped sub-pole 35.

The arrangement is such that the first pole 5 has the greatest number of sub-poles and successive poles 5, l3, and 14 have successively smaller numbers of sub-poles. The final pole 14 may have a single sub-pole if so desired and as shown in the drawings. Obviously the exact number of sub-poles for each upper pole piece may be varied as desired.

The space between and on opposite sides of the V-shaped sub-poles of each upper pole is filled by wooden pieces. This construction is shown most clearly in Figures 6 and '7 where the wooden pieces are indicated by the reference character 29. These wooden members 29 are held in place by means of nonmagnetic screws 30' which are countersunk so that their heads are flush with the bottom surface of the nonmagnetic filler members 29. This construction is for the purpose of providing a flat surface on the underside of the upper pole pieces so that the take-off belts indicated at 39 and 3! for the magnet assembly A and 32 and 33 for the magnet assembly B will ride flatly against the flat bottom surface of the upper poles without any possible chance of cutting the belt.

It is preferable to extend the upper pole pieces laterally outwardly in the direction in which the under stretch of the take-off belts travel. For example, in Figure 4 where the take-off belt 32 and the pole piece 13 are illustrated it will be seen that the pole piece is extended in the direction of travel of the lower stretch of the belt. It is to be noted also that the lower stretch of the take-off belts is the tight side of the belt and the upper side is the loose side. For instance, in Figure 4 it is to be noted that the driving pulley is the pulley 36, the belt passing over the pulley 36" on the other side of the machine.

Each magnet assembly is provided with an individual motor for driving its pair of belts. These motors are reduction gear motors with a mechanical adjustment to vary the speed of the individual motor. The motors are indicated at 36 and 31 in Figure 1.

The lower poles of the magnet assembly A and the first lower pole piece of the magnet assembly B are each equipped with means arranged to provide an adjustment of the relative strength of the successive zones for each air gap. This is shown most clearly in Figure 6. From Figures 6 and 7 illustrating the construction for the pole pieces 15 as well as from Figure 3 showing the pole pieces 1, 8, and I5, it will be seen that each of these pole pieces has an articulated portion. This portion consists of a half-round magnetic member 38 extending transversely across the lower pole l5 and socketed within a semicircular depression in such pole piece. The pole piece 15 i provided with end plates 39. A lug 49 extends laterally outwardly from one side of the pole l5 and loosely carries an adjustable bolt 41 which is pivotally secured as indicated at 42 to the half-round transversely extending magnetic member 39. The bolt 41 is adjusted by means of nuts 43 located on opposite sides of the lug 46 so as to get a micrometer adjustment, so to speak, of the angle of tilt of the upper flat face 44 of the half-round magnetic member 38. After the proper adjustment is secured the nuts 43 are locked and a set screw 45 extending through one of the plates 39 is also set so as to securely lock the half-round magnetic member 38 in its adjusted position. The halfround adjustable magnetic member for the pole 1 is indicated by the reference characte 46 and the half-round magnetic member for the pole 8 is indicated by the reference character 41.

It will now be seen why it was desirable to have the upper side of the belt sag slightly. The purpose of this as will be seen from reference to Figure 3, is to cause the belt to lie flatly against each of the flat angular disposed upper faces of the magnetic members 46, 41, and 38 and to lie flatly against the flat upper face of the pole I6.

It is preferable to adjust the member d6 so that is upper fiat face has the greatest slant and to adjust the member 38 so that its upper fiat face has the least slant. The upper fiat face of the memast ma the=p01e I 3. Material: orverylow; permeability w ill henna-11 attracted to the single sub pole" 35 ofthe-pole. l lr It-is-thusappa'rent thatieach of the poles 5,6, and' l3 secure adiiferential. or graded separation t material at each; airv gap. By means hereinafter; described, it will: be seen. thatevenwith a single-sub-pole as, for example. the sub-pole- .i'iofthepold l4; aimultiplaseparaa tion can besecuredi. ldowever returning. to the poles -5,- 65- and I3 it willbeaseentthat the most:

mater-ia'L-a plurality or hoppersare provided,.one;

for eachsub-pole. For; example, as shown, in Figure 4 two: hoppersindicated by. the reference: characterstt and 49. are; provided: in. alignment with the sub-poles 34. It istobe'. noted alsoithat each of the peles 5:, 5.13,.and 14 project laterally towards thedirection of. travel of. the: under stretch of the take' o'ff belts, see Figures:4 and.'7. The result of thisis that the materialclings tov the. underside of the take-01f belts and remains in its particular zone or separation. The projectingportionstaper upwardly away from the take-off belts and consequently: theseparated material falls into its appropriate hopper when it iscarried by thetake-off belts past: the influence of the separator poles.

As shown in Figure 5-, it is possible to use. a' single \/-'-shaped pole structure, for example the last pole l4; and yet secure a multiple separation. It is to be noted that the. underside of the pole It is tapered upwardly away from the corresponding take-oft belt 33. Thus. as the material gradually carried out of the influence of the: magnet pole, theless permeable material will falldownwardlyfrom the underside of the takeoff belt 33 first and the more permeable material will fall offat a later instant. Consequently by dividing the chute 50, see Figure-5,-into two portions-5+ and 52 it is possible to have a multiple separation with'only one-projecting portion. The particular point at which thediv-isionbetween the separated: parts is to be made is determined by means oi an adjustable flap or divider53.-

It is tobe-noted particularly that this invention-providesmeanswhereby a plurality of separations ismade at a single air gap, thus providing a machine-which isextremely compact and. of simple construction and which for eachmag-- net assembly provides a" large number of separations. It will; thus be seen that this machine is adapted for use with a single magnet assembly if so desired but which is so arranged that a thoughla singleimagn'et assemblyisi'employedz It will also: be-is'e'err thatiany desiredinumber of:mag netassembli'es can'.be employeditwo. for instance, having been shown inLFi'gure's? 1,2; and. 3, thus increasing. the total number'ofl separations for one; passage of thematerial throughthemachine;

It is to: be" understood that the. construction;

shown in Figure 5 for the lastipole' ['4 may. betem ploiyedl for each. oi. the several sub-poles of the remaining polesif so desired.

The: machine: may take other forms. For in stance,v as inxFigure 8, a:- diagrammaticlillustration of amodified form is shown; In this. figure a; single.- magnet assembly. is emplbyedit and is: composed of the energizing winding 54,.171160016'; or yoke: 55,-.an'd. the main poles 5.6 and. 51.. These:

main: poles: respectively dividei into branchzpoles:

5B and59' for the pole 56;. and Gill and E1 forthe pole" 51.. Each of these branch poles isrprosvided'withone or more V -shapedsub-poles. For;

example;the branch pole 5'8 isprovided with four sub-poles 62; the. branchpolel 59- with three:subS-- poles 63'; and'the:branchpole:6 0*with.two:sub-- poles" 66, andt'the branch pole" 6| with a. singlet sub-pole 651 The lower pole. structure is: indi cated byth'e reference character. 66 and is pro-- vided with. a projecting pole adj a'cent: and. below eachiof the: poles 58, 59, 6B, and 61. At leastthe: first: three of. these lower poles is provided with half-round magnetic member ET. A feed belt and take-on belts similar to those previously. described are provided and are drivenin exactly the same manner as described in connectionzwiththe: first form of: the invention.

In this modified form of the invention shown in Figure 8, it will'b'e seen that there is a singleenergizing winding and that the main poles are divided or splitup into several branch: poles and thebranch poles are providediwith one or more-. sub-poles. The space between and just beyond the sub-polesis filled by nonmagneticmembers, suchas-the wooden member correspondingto the member 29- of Figure 7 The same arrangement of hoppers is employed with this form of the in-- vention as with that previously described and the component parts of the-magnet assembly are supported in any suitable manner not shown.

Obviously" the hopper construction associated with each of the sub-polesmay besingle hoppersor may be of the same construction as shown in- Figure 5 and previously described;

If desired nonmagnetic spacers maybe positioned above each of the flat faces-of the articu-- lated portions of the lower poles in any form oil the invention in accordancewith the usual prac-' tice'.

In further explanation of" the invention attention is called to the first form shown in Figures 1 through 7. It is tobe' noted that each magnet assembly can be individually adjusted to vary the s'p'aceof the pole structures and to' thus vary the flux distribution or intensity at the air gap, the. adjustment of opposite ends of each magnet as-- sembly' being independent. This adjustment brings the poles closer together or spaces them farther apart and thus simultaneously varies the large number of separations iaobtained even- 7 of-"thesuccessive subi-polesformedion the upper poles and consequently determines the relative degree of separation for successive sub-poles.

It is to be noted that by providing a plurality of upper sub-poles that it is within the realm of this invention to adjust the lower pole so as to have a horizontal, flat lower pole face. Even with this adjustment it is to be noted that a plurality of zones of separation are produced. Consider several particles of different reluctance. If the first particle is sufiiciently permeable it will be picked up at the first sub-pole. The second and third particles will receive a certain degree of premagnetization from the first sub-pole but will not be picked up by the first sub-pole. When they arrive at the second sub-pole, assuming that particle number two is more permeable than particle number three, particle number two will be picked up by the second sub-pole and particle number three will receive a further degree of premagnetization. When particle number three arrives at the third sub-pole it will be picked up by the third sub-pole. Time to overcome the reluctance to magnetization is allowed by the passage through successive zones. Thus it is possible even with a fiat, horizontal lower pole to secure differential separation at a single air gap.

It will be seen that a very simple and compact separator has been provided which has a relatively small number of parts and yet obtains a vast number of differently graduated, separated products.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention ma be variously embodied and is to be interpreted as claimed.

I claim:

1. A magnetic separator comprising a magnet assembly including an upper and a lower pole spaced apart to provide an air gap and having flat opposed faces, said upper pole having a plurality of nonadjustable sub-poles of like polarity, the fiat face of said lower pole being arranged for angular adjustment, a feed belt and a take-oil belt arranged to travel through said air gap with the take-oil and feed belts respectively flatly contacting the fiat faces of the upper and lower poles, the angular adjustment of the fiat face of said lower pole being arranged to vary the relative intensity of said sub-poles from equal values through any desired range.

2. A magnetic separator comprising a magnet assembly having a plurality of air gaps with upper and lower poles defining the air gaps, the upper poles having a plurality of downwardly projecting nonadjustable sub-poles and the lower poles comprising at least three rotatably mounted adjustable portions having fiat faces arranged to be angularly adjustable to thereby vary the relative magnetic intensity of different portions in each of the several separating zones within a unified magnetic field in accordance with the degree of slant of the corresponding fiat face, a feed belt and transversely extending superposed take-elf belts passing through the air gaps, means for driving the take-oif belts, and means for driving the feed belt and arranged to produce a slack in that stretch of the feed belt passing through the air gaps to cause said feed belt to lie flatly against the adjustable flat slanting faces of the lower poles in all positions of adjustment of the flat slanting faces of the lower poles.

3. A magnetic separator comprising a magnet assembly having a plurality of air gaps defined by upper and lower poles, said upper poles having downwardly extending sub-poles and said lower poles having fiat slanting faces located below said sub-poles, a feed belt having an upper stretch passing through said air gaps and having a lower stretch below said magnet assembly, a drive pulley and an idler pulley, respectively, located at the feed end and discharge end of said feed belt, feed means for feeding onto the upper stretch of said feed belt at a point after said feed belt has left said drive pulley, brake means on said idler pulley to hold the lower stretch of said feed belt tight while allowing the upper stretch of the feed belt to make full contact on the flat slanting faces of said lower poles, and take-01f belts passing transversely of said feed belt through said air gaps.

4. A magnetic separator comprising a magnet assembly having an air gap defined by an upper and a lower pole, said upper pole having a plurality of downwardly projecting and tapering nonadjustable sub-poles arranged to form parallel ridges, said lower pole having a semi-cylindrical magnetic member socketed in said lower pole and having a fiat upper face and adapted to be adjusted to vary the angularity of said fiat upper face to thereby vary the relative intensity of the sub-poles, and an upper take-off belt and a lower feed belt arranged to travel through said air gap at right angles to each other.

5. A magnetic separator comprising a magnet assembly having an air gap defined by an upper and a lower pole, said upper pole having a plurality of downwardly projecting and tapering nonadjustable sub-poles arranged to form parallel ridges, nonmagnetic fillers between the said ridges to provide a fiat lower face for said upper pole, said lower pole having a semicylindrical magnetic member socketed in said lower pole and having a fiat upper face and adapted to be adjusted to vary the angularity of said fiat upper face to thereby vary the relative intensity at the sub-poles, and an upper take-off belt and a lower feed belt arranged to travel through said air gap at right angles to each other.

6. A magnetic separator comprising a magnet assembly having an air gap defined by an upper and a lower pole, said upper pole having a plurality of downwardly projecting and tapering nonadjustable sub-poles arranged to form parallel ridges, said lower pole having a semi-cylindrical magnetic member socketed in said lower pole and having a fiat upper face and adapted to be adjusted to vary the angularity of said fiat upper face to thereby vary the relative intensity at the sub-poles, an upper take-off belt and a lower feed belt arranged to travel through said air gap at right angles to each other, and means for securing a micrometer angular adjustment of the flat face of said semicylindrical member.

'7. A magnetic separator comprising a magnet assembly including an upper pole and a lower pole spaced apart to provide an air gap, a feed belt and a superposed take-off belt arranged to travel at right angles to each other through said air gap, said upper pole having a plurality of nonadjustable sub-poles forming parallel downwardly projecting elongated ridges extending transversely with respect to the feed belt and extending longitudinally with respect to the take-ofi belt, whereby material lifted from said feed belt will be arranged in parallel zones on the under side of said take-01f belt, said lower pole having a fiat face and being rotatably mounted and arranged to have the fiat face slant upwardly towards the most rearwardly located sub-pole with reference to the direction of travel of said feed belt, to therebyprovide relatively diflerent magnet'lc intensities at the separating zones or the nonadjustable sub-poles, said lower pole being at least coextensive in length measured in the direction of travel of the feed belt as said upper pole, and a -plurality of hoppers arranged side by side to "receive the material separated into the several zones on the take-o1! belt. 1

ROSWELL H. STEARNSt REFERENCES CITED The following references are of record in the file of this :patent:

UNITED STATES rams Number Name Date Vance Dec. 19, 1905 Moflatt July 10, 1906 Ullrich Mar. 2, 1915 Manegold July 22, 1919 Woodworth Apr. 15, 1924 Brubaker Nov. 14, 1933 

